Specifications, Service and Repair of Farm and Lawn Tractors


Massey Ferguson 6455 Tractor Specs Overview

Engine Massey Ferguson 6455 Tractor

Power at 2200 rpm, ISO hp (kW) - 100 (74)
Model - PERKINS 1104C-44T
Number of cylinders/displacement - 4 / 4.4 Turbo
Injection pump - Lucas DP 210
Fan - Viscostatic
Alternator - 80 A

MF 6455 Tractor Gearbox

Gearbox model - GBA25 (6x4)
Clutch/shuttle - Power Shuttle
Type - Dyna-6
AutoDrive - optional
Creeper unit 4/1 - optional
Creeper unit 14/1 - optional

Rear axle Massey Ferguson 6455 Tractor

Axle model - GPA40
Final drives - HD
Axle shaft D - 76 mm
Flanged shaft - standard
Brake discs per trumpet housing - 1
Hand brake discs - 3
Differential lock - Dog clutch


Stabilisers - telescopic
Multi-hole drawbar - optional
3-point linkage - Cat. 2, hook or ball type
Clevis hitch - Fast-setting or pin-adjusting scale
Automatic clevis hitch - Fast-setting or pin-adjusting scale
Hitch stud - Stud or auto-hitch
Swinging drawbar - standard
Roller type swinging drawbar - optional

MF 6455 Tractor Power take-off

Type - Interchangeable / shiftable shaft
540/1000/eco - optional
750/1000 - optional
Number of clutch discs - 4
PTO brake - hydraulic
Proportional PTO - optional
Automated PTO - optional
Front power take-off - optional

Front axle

Model - AG 85
Type - fixed or suspended (optional)
Rotational direction - Clockwise
Number of clutch discs - 5
Swivelling mudguard (4WD) - optional
2-wheel drive - optional
Front linkage (optional) - 2.5 T

Massey Ferguson 6455 Tractor Hydraulics

Open Centre 57 l/min - optional
TFLS 100 l/min - optional
Closed Centre 110 l/min - optional
Orbitrol steering - 125 cc
Brake master cylinder - standard
Braking assistance - optional
Trailer brake - optional
Auxiliary spool valves (maximum number) - 4 electrohydraulic (2 SMS) or 4 mechanical
Couplers - Decompression


Transmission control - two AUTOTRONIC 5
Instrument panel - DCC2
Linkage controller - AUTOTRONIC 5
Draft sensors - 2
Sensor capacity - 4 T (standard) or 6 T (optional)
Datatronic - optional
Dual control (front and rear) - optional
TIC with/without draft sensor - optional
Fieldstar - optional


Suspension - optional
Rear-view mirrors - manual (standard) or electric (optional)
Air conditioning - manual (standard) or automatic (optional)
Standard bonnet - Fixed
Bonnet option - Hinged
Standard roof - standard
High-visibility roof - optional
Sloping bonnet - optional

Massey Ferguson 6455 Tractor Engine Overview

The Perkins 1104C-44T engines used for the MF6455 range comply with emissions standards imposed by the authorities (EU97/68/EC Stage 2 / EPA 40 CFR 89 Tier 2).

The quality of fluids used in these engines, as well as the servicing schedule, must be respected in order to keep pollution emission levels low and to maintain the tractor's performance throughout its service life.

Fuel quality

The fuel must comply with standard DIN EN 590 and with the following specifications:

- density (at 15°C): 0.82 to 0.84 Kg/dm3
- viscosity (at 40°C): 2 to 4.5 mm2/sec
- Cetane Index: min 51
- sulphur content: max 0.005 p-%
- water content: max 200 mg/kg

Oil quality

The oil used must comply with the API CH-4 standard.

Coolant quality

The coolant used must comply with the ASTM D 3306 standard.

It must consist of pure water and ethylene/propylene glycol type antifreeze in the following proportions:

- 40–60% water
- 40–60% antifreeze

The ideal ratio is around 50% water to 50% antifreeze.

MF 6455 Tractor GPA40 rear axle

The GPA40 rear axle comprises four housings:

- the centre housing

On the inside, it supports:

- the rear differential assembly and ring gear;
- the pinion;
- the PTO clutch

On Massey Ferguson 6455 Tractor fitted with GTA1540 transmission, the sensor located at the top of the centre housing, towards the front, measures the engine speed at the PTO clutch input;

- the 4WD clutch;
- the hand brake control mechanism;
- the annular pistons and main brake discs

On MF6455 Tractor fitted with GTA1540 transmission (50 kph), the braking surface of the annular pistons and brake discs is optimised.

A mechanical device controls the return of the annular pistons and cancels out any play resulting from the friction of the discs on the annular pistons when braking;

- the ParkLock device (depending on option);
- the creeper unit control mechanism (optional).

On the outside, it supports:

- the right and left-hand hydraulic cover plates;
- the supports fitted to the upper part of the centre housing holding the support and linkage arms.

On Massey Ferguson 6455 Tractor fitted with GTA1540 transmission, the centre housing is reinforced where the linkage support and rear PTO housing are attached.

This is the case regardless of the tractor speed (40 or 50 kph).

- the PTO housing

It supports:

- all variants of the PTO transmission;
- the PTO brake.
- the right and left-hand trumpet housings

These are fitted to either side of the centre housing and house the rear wheel drive system.

On MF 6455 Tractor fitted with GTA1540 transmission, the number of tapped holes used to attach the trumpet housing to the centre housing differs according to the type of trumpet housing:

- Normal Duty and Heavy Duty trumpet housings: 9 tapped holes;

- sealed Heavy Duty trumpet housings: 15 tapped holes;

- trumpet housings with composite final drive: 15 tapped holes.

The trumpet housings are sealed by special seals located:

- for Heavy Duty and sealed Heavy Duty trumpet housings: in the trumpet housings and between the trumpet housings and centre housing;

- for Normal Duty trumpet housings: between the trumpet housings and centre housing;

- for trumpet housings with a composite final drive: between the trumpet housings and centre housing.

In this section, only a partial description is given of each component, as more specific and detailed descriptions are given in their respective sections.

Massey Ferguson 6455 Tractor Robotic mechanical gearbox GBA25

The GBA25 gearbox is equipped to MF6455 Tractor with Dyna 4 transmission. This transmission is fully automated. It allows shifting between all the ratios without declutching.

The gearbox is divided into two parts:

- The Powershift module, with four ratios for shifting under load.
- The robotically-controlled mechanical gearbox with four ranges.

The transmission assembly is controlled electronically by an Autotronic 5 calculator. The Massey Ferguson 6455 Tractor GBA25 Dyna-4 gearbox has 16 ratios.

These are provided by 4 Powershift module ratios for shifting under load, and 4 mechanical gearbox ranges. The mechanical gearbox ranges are controlled like a ratio for shifting under load.

The ratios are controlled by two levers:

- Power control lever located under the steering wheel.
- gear shift lever located on the armrest.

The mechanical gearbox is located between the Powershift module and the rear axle. It comprises two shafts (upper and lower shaft lines), on which four gear trains with helical teeth rotate.

Input drive is supplied by the Power Shuttle and is transmitted to the upper shaft line. Output drive is transmitted via the lower shaft line to a creeper unit or directly to the crown wheel and pinion.


The lubricating oil coming from the 5 bar valve of the MF 6455 Tractor is sent to the gearbox lower shaft line and upper shaft line. A network of internal channels directs the oil to the elements requiring lubrication.

Ratios are selected using two synchronisers, one single cone and one double cone. Each synchroniser is engaged individually.

The synchronisers are controlled by two selector rails and two forks. Each selector rail has a double-acting piston, allowing range shifting. The selector rail pistons are controlled hydraulically via the tractor 20 bar circuit.

Four solenoid valves located on the right-hand side of the gearbox control selector rail movement. Four switches inform the calculator of the selector rail positions.

The switches are pressed in by pins. Each range has a corresponding solenoid valve and switch.

Description and kinematics of ratios

The Massey Ferguson 6455 Tractor robotic gearbox allows four ratios to be obtained with only four gear trains, two shafts and two synchronisers.


Range 1 - The reduction is carried out on three gear trains. The first gear train drives the second train via the 1st gear synchronisers, then the third train.

Range 2 - The reduction is carried out on the first gear train. The 2nd gear synchronisers secure the 2nd gear pinion to the secondary shaft.

Range 3 - The reduction is carried out on the third gear train. The primary shaft is secured to the 3rd gear pinion by the 3rd gear synchronisers.

Range 4 - The reduction is carried out on the fourth gear train. The primary shaft is secured to the 4th gear pinion by the 4th gear synchronisers.

In forward position, input drive comes directly from the Massey Ferguson 6455 Tractor Power Shuttle to the primary shaft. In reverse position, drive comes from the

Power Shuttle via the pinions and the shaft. It enters via the second driven pinion, which is constantly meshed to the primary shaft.

Primary shaft

The primary shaft is splined to the Power Shuttle forward hub. It is supported by two taper roller bearings.

Adjustment is controlled by shims. The PTO shaft is inserted through the centre of the primary shaft.

This cavity in the shaft also serves as a channel for lubricating oil. The first and second driving gear is cut into the primary shaft.

The double pinion turns idle on the shaft and is supported by two taper roller bearings and two needle bearings.

This pinion is supported on the shaft by shims. The fourth driving gear turns idle on the shaft. It is supported by a lubricated bush.

Secondary shaft

The secondary shaft turns on two taper roller bearings. Bores in the centre of the shaft ensure proper lubrication.

Adjustment is controlled by shims. The pinion turns truly on the shaft and is supported by two taper roller bearings and a needle bearing.

The pinion acts as a bearing to the idle pinion. This pinion is in direct contact with the pinion.

A layer of oil ensures the mating faces are lubricated. The pinions and are splined to the shaft. They are separated by a spacer.


The single cone synchroniser located on the primary shaft allows shifting between the third and fourth gears. Its hub is splined to the shaft. It is held in position by a circlip on one side and by the bearing cone fitted tightly on the shaft.

By moving the slider, the shaft is locked either:

- with the double pinion (3rd)
- with the pinion (4th).

The double cone synchroniser located on the secondary shaft allows shifting between the first and second gears. Its hub is integral with the pinion. It is held in position by the snap ring.

By moving the slider, the shaft is locked either:

- with the idle pinion (1st)
- or with the pinion (2nd).

Selecting ratios

The synchronisers are controlled conventionally by forks and and selector rails and. The selector rails are controlled hydraulically. The selector rails are controlled by double-acting pistons.

On the selector rail that controls the 1st and 2nd gear synchroniser, the piston is damped by a spring to give smooth shifting between ranges 1 and 2.

The selector rails are adjusted by tightening or loosening the castellated nuts and. Once adjusted, the stops are held in position by screws and.

An interlock mechanism comprising two rods and a locknut prevents the selector rails from being engaged simultaneously. When one selector rail is engaged, the pin locks the other rail in a groove.